The present invention relates to solar heating systems and means of storing heat for use at a later time.
In the past there have been a great many solar heating systems including the utilization of lens or parabolic dishes for directing solar energy against a heat-absorbing surface which is used to heat water or other materials for transfer to a building to be heated.
Solar heating is also accomplished by placing thin rectangular or square containers having copper water pipe passing in a serpentine fashion over the bottom thereof on the roof of a building. The bottom of the containers can be painted black and a glass cover can be placed over the tubes and the container filled with water, if desired, so that the sunlight hitting the roof will pass through the glass and be impinged upon the black surface which absorbs the heat and heats the water. The copper pipe acts as a heat exchanger for the system to transfer back into a building for heating the building or the hot water used in the building. Similar systems have also been utilized for heating swimming pools to increase the temperature of the water in the pool. A major problem with solar heaters has been the storage of the energy or use at a later time. The system may be very effective during sunlight, but loses its effectiveness on cloudy or rainy days and during the night time. In order to store the heat for evening use it has been suggested to place large tanks in the ground and have the heated water from the solar heater fed into the tanks to heat the water in the tanks underground which is stored and utilized to heat the house in the evenings. Similar storage systems have utilized earth which has been wet, as well as sand, stones, bricks, and the like, which are heated by the solar heating system. A heat exchanger removes the heat from the stored heat in the heated rocks, gravel, or the like, for transfer into the building in the evenings. These systems lose their desirability because of their short term storage and because they have little effect during any lengthy period of cloudy or rainy weather. This is especially true of those areas which have a considerable number of cloudy, rainy days during the year, especially during the winter time when the heat is most desirable, but when the daytime hours are shortest.
The present invention overcomes some of the disadvantages of the prior art by providing for long term storage of the solar energy which can then be utilized at any time desired.